Sanding relay



March 10, 1942. L. l. PICKERT 2,275,647

SANDING RELAY Filed July 10, 1941 2.Sheets-Sheet l v Summer 62 ,1111 LL-i/Jze/z/b attorneys March 10, 1942. I. I=ICKERT SANDING RELAY 2Sheets-Sheet 2 Filed July 10, 1941 (Ittomcgs m2 mw & MNH

air and the other for cleanout air.

Patented Mar. 10, 1942 SANDING RELAY Lynn I. Pickert, Watertown, N. Y.,assignor to The New York Air Brake Company, a corporation of New JerseyApplication July 10, 1941, Serial No. 401,832 7 4 Claims.

This invention relates to sanders for high speed railroad trains andparticularly to improvements in a relay device described and claimed inthe patent to Campbell No. 2,243,244, May27, 1941.

The relay described in the Campbell patent above identified is designedto control a sand trap having two air connections, one for sandingnormally inactive in a running position and as it moves towards thesanding position hesitates or dwells in an intermediate cleanoutposition in which it causes air to be delivered both to the sandingconnection and to the cleanout connection of the sand trap which itoperates.

, The effect is to blow the sand delivery hose free of any obstructionsso that free sanding will occur when the relay completes its fulltraverse and reaches sanding position. In that position i the relaycauses air to be delivered to the sanding connection alone, the cleanoutconnection being vented. On the return traverse from sanding towardrunning position, the relay also dwells in the cleanout position inwhich air is delivered to the cleanout connection alone.

The purpose of the present invention is closely related to this seconddwell which, under certain circumstances, has been found to be undulylong .so that compressed air is needlessly wasted in a protractedcleanout blast. The invention shortens the duration of the dwell andconsequently of the cleanout blast. To understand this problem, it isnecessary to explain the way in which the relay is controlled.

The Campbell patent shows two control mechanisms for the relay. One ofthese is an electricallyactuated admission and exhaust valve which iscontrolled through a train circuit from the head end of the train. Thiselectrically controlled mechanism imposes no undue delay in the finalcleanout dwell. In certain instances the electrical mechanism may beomitted altogether as is fully explained in the Campbell patent.However, it is often used and will be included in the disclosure of thepresent application to illustrate that it may be used withoutinterfering with the successful operation of the present invention.

The second control for the relay is a pneumatically operated admissionand exhaust valve which responds to a brake applying function of the airbrake system and which produces a sanding sequence in which it controlsthe motion of the relay from rumiing position to sanding position andback to running position'within a time period whose duration isdetermined by the vol- The relay is ume of a timing reservoir. Where therelay is used merely to produce a preliminary and very brief sandingsequence, as is the casein the preferred embodiment described in theCampbell patent, the volume of the timing reservoir is small and henceexercises no seriously disturbin effect on the final cleanout dwell ofthe relay, but Where this relay is used to produce sanding cycles ofconsiderable duration, say ninety seconds, as is also proposed in theCampbell patent, the volume of the timing chamber is much larger, andwhen added to the volume'of the delay chamber which forms a part of therelay increases unduly the second or final cleanout dwell of the relay.

. The purpose of the present invention is so to relate the timingchamber to the relay mechanism that the timing chamber is allowed toperform its normal function in limiting the overall duration of thesanding cycle without materially increasin the final cleanout dwell ofthe relay. Advantage is taken of the fact that when the relay is movingoutward towardsanding position the dwell occurs when both the sandingand the cleanout connections are in communication with the air supply,whereas, in the second dwell, which occurs when the relay is moving fromsanding toward running position, the sanding connection is vented andthe cleanout connection alone is connected to supply. Thus th relay hasan asymmetric characteristic and this is availed of to isolate thetiming reservoir from the delay chamber and charge the timing reservoirfully, with the result that the delay chamber alone times the dwell inessentially the same way that it times the dwell under electric control.

The invention will now be described by reference to the accompanyingdrawings in which:

Fig. 1 is a diagram of the braking and sanding equipment for one car ofa train.

Fig. 2 is a diagrammatic section of the relay valve including itselectrical and pneumatic controls. (The parts are shown in running orinactive position.)

Figs. 3, 4 and 5 are diagrams of the slide valve components of the relayshowing respectively preliminary cleanout position, sanding position,and final cleanout position.

It may be remarked that Fig. 1 shows a car equipment similar to that ofFig. 2 of the Campbell patent and thus represents the equipment for carsother than the motor car.

The system can be controlled by mechanism such as that shown in Fig. 1of the Campbell patent; it can be controlled as indicated in Fig. 9 ofthe Campbell patent, and in fact is available give a full understandingof the cleanout and sanding characteristics of such a trap.

Refer first to Figs. 2 to 5 inclusive, which views are diagrams to theextent that the ports are drawn as if they all lay in a common planewhich is the plane of section.

The. entire relay is carried on a pipe bracket H which is supported onthe car and to which all pipe connections are made, The sanding air lineappears at E2, the clean-out air line at l3, the sanding supplyreservoir connection, which furnishes all operating air, at it, and thetiming reservoir connection at i5. is from the sanding port of thecontrol valve, as will be explained, and is the connection through whichthe relay is put into action by emergency response of the control valve.Leading from the connections l2 to is inclusive are freely communicatingpassages formed in the bracket and in the connected housings. For thepurpose of reducing the number of reference numeralsancl simplifying thetracing of ports, these interconnected ports and pipes are considered asforming continuous passages and are given a single reference numeral. Inaddition to the passages which form continuations of the pipes I2 to I5inclusive, the bracket and connecting housings are formed with anexhaust port [[7, and the bracket I l encloses a chamber l8 whichparticipates in a timing function hereinafter described.

Mounted on one side of the bracket H is a housing H) which encloses thepilot slide valve mechanism of the relay as well as the piloted poppetvalves. In the upper portion of the housing l9 are mounted a slide valvechamber bushing 2i and a cylinder bushing 22. Working in the cylinder 22is a piston 23 which has a stem 24 extending into the slide valvechamber within bushing 2! and terminating in the spider 25 which guidesthe stem. Mounted for lost motion between the shoulder 25 adjacent thepiston and the spider 25 is the main slide valve 2?. This has wings 28which straddle the piston stem 24 and which carry a bow spring 29arranged to hold the valve 21 against its seat. Between the wings 23 theback of the slide valve 27 is formed with The connection I ii a seat fora graduating slide valve 35, which is closely confined between theshoulders 32 and 33 on stem 24 so that the graduating valve .partakes ofall of the movements of the piston 23.

Piston 23 is urged to the right by a duplex spring assembly so arrangedthat only one of its two concentric springs resists the motion of thepiston to the left through that part of its travel corresponding to thelost motion of the piston relatively to the main slide valve 2i. At thelimit of such motion both springs oppose motion of the piston.

The main or primary spring is shown at M and is confined under stressbetween an inner spring seat 35 and an outer cuped spring seat 36. Thesetwo spring seats are connected together by a headedstem 37 which isslidable through a bushing 38. This in turn is slidable axially throughthe spring seat 33 for a limited range corresponding to the lost motionjust mentioned. The spring seat 33 seats within'the end of a closure cap39 which closes the outer end of the cylinder 22. The cap is sealed by agasket, as shown, and the gasket projectsinward far enough to serve as aseat for the piston when the latter arrives at the outer limit of itsmotion.

The secondary spring M is a lighter spring mounted concentrically withinthe spring 34. It is sustained at its inner end on the spring seat 35and is sustained at its outer end on the cupped spring seat 42, which isthimble-like in form, engages the end of bushing 38 and telescopes overthe spring seat 33. Its telescoping motion is limited by the bushing.33. The action is as follows: When the piston 23 moves outward, it isopposed initially by the spring 34 until the spider 25 engages the slidevalve 21 and is about to move it; At this point bushing 33 and springseat 42 reach their limit of motion. From then on the resistance of theinner spring H is added to that of the spring 33. The purpose is tocause the piston to pause momentarily at the limit of motion of thegraduating valve 3! relatively to This eifect is had in both is mountedare three ports; a cleanout air control port 47, a branch of the exhaustport 11, and a sanding air control port 48. In the valve 21 andcommunicating with the port 48 in all positions of the slide valve is athrough port 49; An enlargement at the bottom of the port 49 is themeans to maintain communication between it and the port 4-8 in allpositions of the slide valve 21. Also formed through the slide valve 21is a port 5| which is enlarged at its bottom so that it communicateswith the exhaust port I! in all positions of the slide valve. This porthas an extension 52 leading outward and thence .to the graduating valveseat in the back of the slide valve. In addition there are two impulseports 53 and 54 which lead through the slide valve.

The graduating Valve has two cavities in its lower face,- namely 55 and56, and has drilled through it an impulse port 51.

These ports are so arranged that in the normal or running position ofFig. 2 cleanout control port 4'! is connected to exhaust port l1 by wayof port 53 and cavity 55, port 52 and port 5|. At the same time thesanding air control port 48 is connected to exhaust port I! by port 49,cavity 56 and port 5|, and port 51 communicates with the port 54 whichis then blanked at the seat.

When the piston starts outward the graduating valve 3| exposes port 49at the same time that port 5'! opens to port 53 and the ports are fullyopen at the limit of lost motion of the graduating valve relatively tothe slide valve. The effect is to admit air under pressure from thesanding 2,275,647 first closes the port 4 a then" the Port 51 registersbriefly with the port 54 (see Fig. 5) to furnish abriefcleanout blast tothe port 41. As above set" forth, the piston pauses momentarily in thepositipn of Fig.5 because at this point the spring 4Ireaches" its limitof expansion. Continuedmovement carries the slide valve inward sothatjport 54rnoves out of register with port 41. Wh'enrunning' position(Fig. 2) is reached,

thf ports 41 and 48 are vented to atmosphere by connection with port IIas already described.

"Mounted" in the lower part of the housing I9 are two poppet valvemechanisms which are con trolled by the admission and exhaust ofpressure fluid to and from the ports 41 and 48 respectively.

Port 41 leads to the space within the cap BI and beneath the flexiblediaphragm 62, the diaphragm being clamped at its periphery between thecap GI and the housing l9 and connected at its center to a thrust plate63 which carries an exhaust poppet valve 64. The space immediately abovethe diaphragm B2 is con-- nected to atmosphere by way of port I1.

When the diaphragm is in its normal lower position the valve 64 is openand connects the chamber 65, to which the cleanout air line l3 leads,with atmosphere. When pressure fluid is admitted beneath diaphragm 62the effect is to force the valve 64 upward, closing the exhaust passage.A lug on the end of the valve 64 strikes afsimilar lug on the lower endof a poppet valve 66 and unseats this valveagainst the opposition of acoil compression spring 61 and the fluid pressure communicated from thesanding supply reservoir line 14 to the chamber 68 above the poppetvalve 66.

Similarly, the sanding control port 43 leads to the space within cap 1|and beneath flexible diaphragm 12. This is clamped at its peripherybetween the cap 1| and the housing 19 and is clamped at its center tothe thrust plate 13, to which the exhaust valve 14, similar to the valve64, is attached. The chamber is connected to the sanding air line 12 andthe valve 14 carries a lug which, when the valve is forced closed,strikes a similar lug on the inlet valve 16 and forces it upward againstthe resistance of the coil compression spring 11 and the pressurecommunicated to the chamber 18 by the sanding supply passage l4.

Thus the two passages 12 and 13 are normally vented to atmosphere by thepoppet valves 64 and 14. If the port 41 is put under pressure, theexhaust passage is closed and a direct connection is open past supplyvalve 65 to the passage l3. Similarly, if the passage 48 is underpressure, the exhaust passage past the valve 14 is closed and the valve16 is unseated to admit air from the sanding reservoir connectiondirectly to the sanding connection [2. In this way a relativelysinallslide valve mechanism, with ports oi comparatively small size, pilotsthe action of inlet and exhaust mechanisms of large capacity.

Electric control is exercised by energizing and deenergizing a winding8| which is mounted un der a cap 62 on a valve body 83' bolted tobracket II. In the housing 83 is a chamber 84 which is in freecommunication by way of port 45 with the chamber 18 already described.The port 46 leading from the space to the left of piston 23 terminatesin valve chamber 85. In the chamber 85 is a double beat poppet valvehaving an exhaust head 36 which coacts with an atmospheric exhaust seat81 and an inlet head 88 which ooacts with the supply seat 89 controllingflow be tween the chambers 84 and 85.

A coil compression spring 9| valve toward the exhaust seat. ing 8! isde-energized, as it isunder running conditions, the exhaust head 86 ofthe double beat valve seals on seat 81 and the port 46 is urges thepoppet When the windconnected by way of chamber 84 and port 45 with thechamber 18, and further by way of choke 44' and filter 43 with the slidevalve chamber within bushing 21. As explained, this chamber is in freecommunication with the sanding supply reservoir line l4. Thus, undernormal conditions, the pressures on the two sides of the piston 23equalize and the springs force the piston 23 to its innermost orright-hand position, shown in Fig. 2.

If the winding 8| is energized, the double beat poppet valve is moveddownward, isolating chamber 85 from chamber 84 so the chamber I 3 re- 1mains charged, and connecting chamber 85 with atmosphere through a flowcontrolling choke 92. It follows that the space to the left of piston 23is vented to atmosphere at a rate controlled by the flow capacity ofchoke 52. The piston moves outward against the resistance of spring 34and just at the limit of lost motion between the piston and the mainslide valve 2? the resistance of the second spring 4| is added, so thatthe piston pauses momentarily in that position and then resumes itsoutward excursion until it seals on the cap gasket. This is sandingposition.

When the winding 3! is de-energized, the double beat poppet valve 85, 88will return to the position shown in Fig. 2, closing the exhaust fromchamber 85 and connecting chamber 85 with chamber 84 and chamber 18. Theresulting increase of pressure on the outer face of piston 23 will startthe return excursion of the piston. Under these conditions the choke 44will exert control on the rate of development of pressure on the leftside of piston 23 and consequently on the rate of inward motion of thepiston.

The structure indicated at 93 is merely a separable connector for theleads and 95, which are connected with the terminalsof the winding 8|.

Bolted to the bracket ii is a housing 96 which contains a chamber 81connected to the exhaust passage 11, and a chamber 93 connected to thetiming reservoir connection l5. A timing reservoir is indicated at $9 inFig. 1 and augments in any desired degree the volume of chamber $8. Theconnection I8 leads to a chamber Hli within the cap 32 and below adiaphragm lot. This is clamped at its periphery between body 96 and cap402 and is connected at its center to the thrust plate I 64. Slidablymounted within the thrust plate 194 and limited. in its outward motionby a stop flange is a plunger m5 which is urged outward by the coilcompression spring ")6. When the diaphragm N33 is forced upward, plungerm5 reacts against an exhaust poppet valve N31 to urge it in an exhaustclosing direction. The pilot of the exhaust valve IE1 is in position tocollide with the pilot of the reversely seated poppet valve H38, whichis urged closed by a coil compression spring m9 and which controls flowfrom the chamber it previously described to the chamber 38 and connectedtiming reservoir 99. The flow is by way of a choke HI and ball checkvalve M2 to the chamber H3 behind the valve N38.

The device so far described is the Campbell sander relay as disclosed inthe patent above identified. To limit the dwell in the final cleanoutposition, the diaphragm valve unit now about to be described is added inan extension of hous-' ing 96.

A chamber H4 in free communication with chamber H3 contains a valve seatH5, to which a branch of the cleanout air passage I3 leads. The upperwall ofchamber H4 is a flexible diaphragm H6 confined at its margin bycap H1, so that there is a chamber H8 above the diaphragm. A branch ofsanding passage I2 leads to chamber H8.

A hub structure I I9 is carried by the center of diaphragm H6. In thisis guided a bushing I2I urged downward by a spring I22. Slidable withlimited lost motion in bushing I2I is the stem I23 of poppet valve I24which coacts with seat HE. A spring I25 reacts between hub H9 and valveI24.

The area of diaphragm II6 greatly exceeds the area of valve I24 so thatwhen chamber H6 is under pressure valve I24 will be held closed.

The connection I6 leads from the sanding port of the brake controllingvalve device and when pressure is developed in connection I6 thediaphragm I93 moves upward, forcing the valve I01 closed and the valveI08 open. The eifect is to reduce the pressure in the chamber I6 andsince this is normally connected by way of port 45, chamber 84, chamber85 and port 46, with the space to the left of the piston 23, theresulting reduction of pressure in chamber I8 causes the piston 23 tomove outward.

The reduction of pressure will continue until timing reservoir 99 ischarged nearly to equalization with the sanding supply passage I4. Choke44 feeds to chamber I8 at a rate less than the outflow through thelarger choke III, at least until reservoir 99 is nearly charged.Ultimately, development of pressure in chamber I8 would cause piston 23to move inward and terminate sanding. This would occur after anappropriate interval, say 90 seconds.

On outward motion of piston 23 there will be a dwell in the position ofFig. 3. In this position sanding air connection I2 and cleanout air lineI3 are both under pressure. Hence diaphragm H6 is subject to pressure inline I2 so that valve I24 is held closed. It is similarly held closed infull sanding position of Fig. 4.

Charging of the timing reservoir will proceed, and as in the Campbelldevice, a stage will be reached when piston 23 moves into the positionof Fig. 5. In this position the sanding connection I2 is vented ventingchamber H8 above diaphragm H6 so that pressure in chamber H4 forcesdiaphragm H6 up and opens valve I24. This permits cleanout air to flowfrom connection I3 which is connected to supply, to chamber H4. Thisquickly charges timing reservoir 99 and closes valve I I2. Hence thedwell in Fig. is timed solely by chamber I8 and is of the short durationcharacteristic of the electric control already described.

Reference will now be made to Fig. 1. The brake pipe appears at I26 andwould be connected from car to .car in a train by flexible hose withcouplings and angle cocks shown in the drawing, all in accordance withthe conventional practice. The brake pipe I26 is connected through theusual cut-out cock and dust collector with the brake controlling valvedevice I2'1, here assumed to be a control valve of the D-22 type. Suchvalves may be used either in an automatic or combined straight airautomatic system but for purposes of explanation a simple automaticsystem is assumed.

The control valve I21 has three connections to chambers in amulti-chambered reservoir I28. These connections are the auxiliaryreservoir connection I29, the emergency reservoir connection 'I3I, andthe displacement volume connection I32. The brake pipe I26 is normallyunder pressure (say lbs.f per sq. in.) and the control valve I21functions in release position to charge the auxiliary and emergencyreservoirs and alsoto deliver air to a supply reservoir connection I33which is in communication with the supply reservoir I34.

From the reservoir I34 the pipe I35 leads to the intercepting valve I36and from the intercepting valve I36 another pipe I31 leads to the sandersupply reservoir I38 to which the pipe I4 already mentioned isconnected. The intercepting valve is controlled by pressure in the pipeI39 in such a way that when the pipe I32 is under pressure, as it isduring a brake application, the reservoir I38 cannot draw on thereservoir I34 for air. Thus the brake supply reservoir is protectedagainst depletion of charge by demands of the sanding system, as soon asa brake application commences. tercepting valve I36 is not shown but itis fully disclosed in the Campbell patent, above identi-' fied.

The control valve I21, in response to a reduction of brake pipe pressurewill establish related pressure in the pipe I4I leading to the admissionand exhaust relay valve I42. The relay valve functions to establishproportionate pressures in the pipe I43 and in the connected brakecylinders I44. The relay I42 is supplied with air from the reservoir I34through the pipe I33.

A pair of sand traps I46 are shown and are illustrated as connected tothe sanding air connection I2 and the cleanout air connection I3 in theusual manner. The pipe I6 leads from the sander control connection ofthe control valve I21 and is connected to the sanding relay as alreadydescribed. The control valve I21 may put the sanding connection I6 underpressure in emergency application or in both service applications andemergency applications, so far as the present invention is concerned.

The winding 8| in the housing 82 is connected across electrical traincircuits I46, I41. These are connected from car tocar by jumpers I48 inthe usual. manner. The electrical controlling mechanism may be actuatedin any known way, for example, it may be operated from the head of thetrain as proposed in the Campbell patent, above identified. Furthermore,the electrical mechanism can be wholly omitted, in which event the relaywould be operated pneumatically under the control of the mechanism inthe housing 96. As explained, a long timing cycle requires a largevolume for the timing reservoir 99 and where the timing cycle is long,the volume of the timing reservoir 99 added to the volume of the delaychamber I8 permits too long a dwell in the final cleanout position ofFig. 5.

The eifect of applicants invention is to isolate the reservoir 99 andcharge it fully as soon as the relay arrives in the position of Fig. 5,so that the excess dwell is not imposed but on the contrary the controlis determined solely by the volume of the delay chamber I6.

As pointed out in the Campbell patent above The structure of the innotlimiting. The invention is useful with any timing relay having similarcharacteristics of timing control, and in which the timing is effectedby a timing reservoir and a delay chamber according to the generalprinciples above set forth.

I claim:

1. In a sanding relay unit, the combination of a housing enclosing aslide valve chamber and communicating cylinder; means for supplying airunder pressure to said slide valve chamber; a piston, working in saidcylinder and separating the slide valve chamber from a working space insaid cylinder; a slide valve and coacting graduating valve connected tobe actuated by said piston, said valves controlling sanding and cleanoutof piston motion inward toward the valve chamher in which both ports arevented, a sanding position at the outward limit in which the sandingport is under pressure and the cleanout port vented, a cleanoutintermediate position assumed in outward motion in which both said portsare under pressure and a cleanout intermediate position assumed ininward motion, in which the cleanout port is under pressure and thesanding port vented; loading means for biasing said p iston and valvestoward running position and for causing them to dwell in saidintermediate positions; a delay chamber forming an enlargement of saidworking space; means affording restricted communication between thedelay and slide valve chambers; a delay suppression chamber in somewhatless restricted communication with said delay chamber; a check valvecontrolling the last named communication and inhibiting flow toward thedelay chamber; a timing chamber; valve means normally serving to ventthe timing chamber and operable to close said vent and connect thetiming and delay suppression chambers; and

, delay suppression means responsive to venting of the sanding portwhile the cleanout port is under pressure and serving when so renderedactive to charge the delay suppression chamber and timing chamber.

2. The combination defined in claim 1 in which there are pressureoperated supply and exhaust valves respectively operated to supplyposition by development of pressure in said sanding and cleanout ports,said pressure operated valves thus supplying sanding air and cleanoutair under the control of the slide valve; and the delay suppressionmeans comprises a valve biased in an opening direction by the pressureof cleanout air and a related and larger movable abutment biased in avalve closing direction by the pressure of sanding air.

3. In a sanding relay unit, the combination of a housin enclosing aslide valve chamber and communicating cylinder; mean for supplying airunder pressure to said slide valve chamber; a piston working in saidcylinder and separating the slide valve chamber from a working space insaid cylinder; a slide valve and coacting graduating valve connected tobe actuated by said piston, said valves controlling sanding and cleanoutports, there being a running position at the limit of piston motioninward toward the valve chamber in which both ports are vented, asanding position at the outward limit in which the sanding port is underpressure and the cleanout port vented, a cleanout intermediate positionassumed in outward motion in which both said ports are under pressureand a cleanout intermediate position assumed in inward motion, in whichthe cleanout port is under pressure and the sanding port vented; loadingmeans for biasing said piston and valves toward running position and forcausing them to dwell in said intermediate positions; a delay chamberforming an enlargement of said working space; means afiording restrictedcommunication between the delay and slide valve chambers; a timingchamber; valve means normally serving to vent the timing chamber andoperable to close said vent and establish a restricted one-Way flowconnection from the delay chamber to the timing chamber; and pressureoperated d'elay suppression means rendered effective by charging of thecleanout port while the sanding port is vented to charge said timingchamber.

4. The combination defined in claim 3 in which the delay suppressionmeans comprises a valve biased in an opening direction by pressure ofcleanout air and a related and larger movable abutment biased in a valveclosing direction by pressure of sanding air.

LYNN I. PICKERT.

